CN221293759U - Planetary gear electric power steering gear for commercial vehicle - Google Patents

Abstract

The utility model belongs to the technical field of automobile manufacturing, and relates to a planetary gear electric power steering gear for a commercial vehicle, which comprises the following components: the motor controller, the input shaft, the output shaft and the worm gear at the power assisting end; the torque of the power-assisted worm gear is reduced, increased and transmitted to the output shaft through the twice planetary gear step-by-step speed reduction and torque increase structure, and the whole vehicle storage battery is used as a power source, so that a hydraulic system is completely abandoned, the problems of high energy consumption, easiness in leakage and environment unfriendly of the hydraulic steering system are perfectly solved, and the cost of the system can be improved due to the reduction of the components of the hydraulic system, and the arrangement and matching of the steering system on the whole vehicle are easier.

Description

Planetary gear electric power steering gear for commercial vehicle

Technical Field

The utility model belongs to the technical field of automobile manufacturing, and relates to a planetary gear electric power steering gear for a commercial vehicle.

Background

With the rapid development of the automobile industry, the intelligent driving technology is developed with the rapid development, an Electric Power Steering (EPS) system is widely used on passenger vehicles, and in recent years, the electric power steering system is gradually used on new energy commercial vehicles, but the structural strength of the existing electric power steering system is limited, and the existing electric power steering system is mainly used for light commercial vehicles.

However, as the load of the steering shaft of the medium-heavy truck is larger, most of the conventional circulating ball hydraulic steering devices are still used in the present medium-heavy trucks, namely, most of the conventional circulating ball hydraulic steering devices are a constant flow type hydraulic power assisting system, an oil pump and a rotary valve are arranged in the system, and the oil pump works along with an engine no matter whether the system works or not, so that the energy loss is serious, and the fuel consumption of the whole truck is increased; when the hydraulic oil works, the hydraulic oil can enter the power cylinder through a tiny gap between the valve core and the valve sleeve to generate noise; the hydraulic steering gear cannot communicate with the whole vehicle, so that the functions of speed-following power assistance, multi-mode steering, lane keeping, crosswind compensation and the like cannot be realized, the driving labor intensity of a driver is high, and the driver is easy to drive and fatigue; based on the above reasons, the electro-hydraulic steering system is applied to the heavy truck in the existing part, namely, a set of electric power assisting system is overlapped on the basis of the hydraulic steering system, so that the functions of speed-following power assistance, steering multi-mode, lane keeping, side wind compensation and the like can be realized although the communication with the whole vehicle is realized, the hydraulic system is not completely abandoned, the defects of high energy consumption and the like are also caused, when the hydraulic system fails, the steering system cannot provide full power, the hand feeling becomes heavy, the risk is easy to generate, and the matching cost is greatly improved due to the additionally increased set of electric power assisting system.

How to realize the turning of the medium-heavy truck commercial vehicle to the pure electric state becomes an urgent need for the turning of the current commercial vehicle.

Disclosure of utility model

The technical scheme adopted for solving the technical problems is as follows: a planetary gear electric power steering for a commercial vehicle, comprising: the motor steering device comprises a motor controller, an input shaft and an output shaft, wherein the power input end of the input shaft is connected to an automobile steering wheel, the power output end of the output shaft is connected to a rocker shaft for providing power for automobile steering, a torsion bar and a torque angle sensor are arranged on the input shaft, and the torque angle sensor is electrically connected to the motor controller;

The motor controller drives the power-assisted end worm to rotate through the output shaft of the motor, the power-assisted end worm is meshed with the power-assisted end worm wheel, the power-assisted end worm wheel is fixedly connected with a coaxially rotating transmission shaft, a coaxially rotating first-stage sun wheel is fixedly connected to the transmission shaft, a group of first-stage planetary gears are meshed on the periphery of the first-stage sun wheel, a first-stage gear ring which is fixedly connected to the shell and provided with annular internal teeth is meshed on the periphery of the first-stage planetary gears, the first-stage planetary gears are rotationally connected with a first-stage planet carrier, the torque output end of the first-stage planet carrier is located on the opposite side of the transmission shaft, the transmission shaft is coaxial with the torque output end of the first-stage planet carrier, and the output torque of the power-assisted end worm sequentially passes through: the power-assisted end worm wheel, the transmission shaft, the first-stage sun wheel, the first-stage planetary wheel and the first-stage planetary frame are subjected to step-by-step speed reduction and torque increase and then transmitted to a torque output end of the first-stage planetary frame;

The torque output end of the first-stage planet carrier is detachably and fixedly connected with a coaxial rotary final-stage sun gear, a group of final-stage planet gears are meshed on the periphery of the final-stage sun gear, a final-stage gear ring which is fixedly connected to a shell and provided with annular internal teeth is meshed on the periphery of the final-stage planet gears, the final-stage planet gears are rotationally connected with the final-stage planet carrier, the torque output end of the final-stage planet carrier is positioned on the opposite side of the final-stage sun gear, the torque output end of the final-stage planet carrier is detachably and fixedly connected with a coaxial rotary output shaft, the torque output ends of the final-stage sun gear, the final-stage planet carrier and the output shaft are coaxial, and the output torque of the torque output end of the first-stage planet carrier sequentially passes through: the final sun gear, the final planet carrier and the output shaft are transmitted to the output shaft after the final sun gear, the final planet carrier and the output shaft are subjected to step-by-step speed reduction and torque increase again;

The stator of the torque angle sensor is fixedly connected with the outer circumference of the input shaft, the rotor of the torque angle sensor is fixedly connected with the outer circumference of the hand-force end worm, the torque angle sensor and the motor controller are electrically connected to the vehicle-mounted ECU, the torque angle sensor outputs the detected torque and the electric signal of the angle to the vehicle-mounted ECU, and the motor controller is electrically connected to the vehicle-mounted ECU; the torque of the motor is converted into large torque power assistance suitable for steering of the commercial vehicle through twice speed reduction and torque increase, the hydraulic system is completely abandoned by completing steering power assistance of the commercial vehicle in a pure electric power assistance mode, the problems that the hydraulic steering system of the conventional commercial vehicle steering power assistance system is high in energy consumption and easy to leak and environment-friendly are solved, and the cost of the system can be improved due to the reduction of parts of the hydraulic system, and the arrangement and matching of the steering system on the whole vehicle are easier.

Preferably, the hand worm is meshed with a hand worm gear, the hand worm gear is detachably connected with the torque output end of the first-stage planet carrier, and the hand worm gear and the torque output end of the first-stage planet carrier are coaxial with a rotating shaft; the hand-force end worm and the hand-force end worm wheel are connected with the torque output end of the first-stage planet carrier in torque, so that the power-assisted reverse torque can be transmitted to the steering wheel of the automobile through the hand-force end worm and the input shaft in real time, and a driver can feel steering torque feedback in real time.

More preferably, the first-stage planet carrier torque output end is detachably fixedly connected with the last-stage sun gear in the following connection mode: spline connection; the torque output end of the final stage planet carrier is detachably fixedly connected with the output shaft in the following connection mode: spline connection; the first-stage planet carrier torque output end can be detachably connected with the hand-force end worm wheel in the following connection mode: the shaft holes are connected in an interference way; the spline connection ensures effective transmission of torque, and the requirement on axial connection precision is not high, so that processing and matching between the shaft and the torque output end of the planet carrier are simpler, more convenient and more reliable, and the interference connection and matching of the shaft hole enable the worm wheel at the hand end to be directly pressed on the torque output end of the planet carrier to effectively transmit torque, so that the torque transmission device is simpler and more reliable.

Preferably, the group of first-stage planetary gears is provided with two to six planetary gears, and the planetary gears are distributed around a rotating shaft of a torque output end of the first-stage planetary gear frame; because the cooperation between the sun gear, the planet gears and the star frame both requires speed reduction and torque increase, the number of teeth of the sun gear is smaller than that of the planet gears, the number of teeth of the planet gears is smaller than that of the inner gear ring, and the planet gears transmit larger torque, so that the torque transmission effect of a single planet gear is poor, the optimal range is two to six planet gears which are annularly and uniformly distributed, the speed reduction ratio can be ensured, and the torque bearing capacity can be ensured.

Preferably, the group of final planet gears is provided with two to six planet gears, and the planet gears are distributed around the rotating shaft of the torque output end of the final planet carrier.

Preferably, the shell comprises a main shell and a lower shell, wherein the main shell is in a groove shape, the lower shell is in a cover shape, and the planetary gear electric power steering gear is sealed after the lower shell is buckled on the main shell; the output end of the output shaft extends out of the lower shell from the lower shell, and the input end of the input shaft and the worm at the power assisting end extend out of the shell from the main shell.

More preferably, an annular locking screw plug is arranged at the end face of the transmission shaft rotary connection shell, and a locking nut is sleeved at the position of the output shaft extending out of the shell; the locking screw plug is screwed into the main shell to axially position the transmission shaft, the locking nut is screwed into the shell along the output shaft and is glued, so that a gap between the output shaft and the shell can be sealed and leakage-proof, and lubricating oil in the power steering gear is prevented from seeping out and external dust and sundries are prevented from entering the shell.

Preferably, the input shaft, the transmission shaft and the output shaft are respectively provided with bearings at the positions of the rotating connection shell, the first-stage planetary gear is rotationally connected with the first-stage planetary carrier, and the last-stage planetary gear is rotationally connected with the last-stage planetary carrier.

More preferably, the bearing of the transmission shaft rotary connection shell adopts a first deep groove ball bearing; the bearing of the final-stage planetary gear rotationally connected with the final-stage planetary carrier adopts a second deep groove ball bearing; the bearing of the input shaft rotary connection shell adopts a third deep groove ball bearing; the bearing of the output shaft rotating connection shell is a tapered roller bearing; the seat rings of the tapered roller bearings are pressed into the shell, the inner rings are in interference connection with the shafts, and the bearing rings can bear axial stress within a certain range while providing good rotational connection stability.

More preferably, the tapered roller bearings are provided with two groups, and the tapered roller bearings are sleeved at the outer circumference of the output shaft and are installed back to back along the axial direction; the tapered roller bearings are installed back to back in the axial direction, so that the axial stress of the output shaft is more effectively counteracted.

The beneficial effects of the utility model are as follows:

1. The utility model provides a planetary gear electric power steering gear for a commercial vehicle, which takes a whole vehicle storage battery as a power source, completely abandons a hydraulic system, solves the problems of high energy consumption, easy leakage and unfriendly environment of the hydraulic steering system, and can improve the cost of the system and make the arrangement and matching of the steering system on the whole vehicle easier due to the reduction of the parts of the hydraulic system.

2. The planetary gear structure is used, so that the planetary gear structure has larger area of gear contact and uniform symmetrical load of 360 degrees, and a plurality of tooth surfaces can jointly and uniformly bear instantaneous impact load, so that the planetary gear structure can bear higher torsional impact and cannot be damaged or broken; the planetary gear transmission has extremely high transmission efficiency (the single stage is 0.97-0.99), has higher torque/volume ratio, can make very large output torque, has the characteristics of high rigidity, high precision and wear resistance, and ensures the reliability and the service life of products.

3. The utility model adopts the pure electric steering gear, so that the driving assistance functions of speed-following assistance, steering multimode, lane keeping, crosswind compensation, automatic parking and the like are easy to realize, the driving experience of drivers and passengers can be effectively improved, the driving labor intensity of the drivers is reduced, and the driving safety is improved.

4. The utility model adopts two-stage planetary gear superposition transmission, can effectively improve the transmission ratio of products and meets the application requirements of medium and heavy trucks; the higher helping hand rotational speed of hand power end feeds back to the motor through first grade planetary mechanism after passing through worm wheel speed reduction, has effectively avoided the phenomenon that the rotational speed that medium heavy truck steering gear transmission ratio is big to lead to is higher than the rated rotational speed of motor.

Drawings

FIG. 1 is a perspective view of the internal engagement of a planetary electric power steering gear for a commercial vehicle;

FIG. 2 is a cross-sectional view of the electric power steering gear;

Fig. 3 is a schematic diagram of the operation.

In the figure: 1. a power-assisted end worm; 2. a power-assisted end worm wheel; 3. locking the screw plug; 4. a first deep groove ball bearing; 5. a transmission shaft; 6. a first-stage sun gear; 7. a first-stage planet wheel; 8. a main housing; 9. a first-stage planet carrier; 10. a hand-force end worm wheel; 11. a hand end worm; 12. a second deep groove ball bearing; 13. a lock nut; 14. an oil seal; 15. an output shaft; 16. a side end cap; 17. tapered roller bearings; 18. a final stage planet carrier; 19. a final stage sun gear; 20. a final stage planet wheel; 21. a lower housing; 22. a final stage ring gear; 23. a torque rotation angle sensor; 24. an input shaft; 25. an upper end cap; 26. a first-stage gear ring; 27. a motor controller; 28. a torsion bar; 29. and a third deep groove ball bearing.

Detailed Description

The following description of the related art will be made apparent to, and is not intended to limit the scope of, the embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

Referring to fig. 1 to 3, a planetary gear electric power steering apparatus for a commercial vehicle includes: the motor controller 27, the input shaft 24 and the output shaft 15, wherein the power input end of the input shaft 24 is connected to the steering wheel of the automobile, the power output end of the output shaft 15 is connected to a rocker shaft for providing power for steering of the automobile, the input shaft 24 is provided with a torsion bar 28 and a torque rotation angle sensor 23, and the torque rotation angle sensor 23 is electrically connected to the motor controller 27;

The motor controller 27 drives the power-assisted end worm 1 to rotate through the output shaft of the motor, the power-assisted end worm 1 is meshed with the power-assisted end worm wheel 2, the power-assisted end worm wheel 2 is fixedly connected with a coaxially rotating transmission shaft 5, a coaxially rotating first-stage sun wheel 6 is fixedly connected to the transmission shaft 5, a group of first-stage planetary wheels 7 are meshed on the periphery of the first-stage sun wheel 6, a first-stage gear ring 26 fixedly connected to the shell and provided with annular internal teeth is meshed on the periphery of the first-stage planetary wheels 7, the first-stage planetary wheels 7 are rotationally connected with a first-stage planet carrier 9, the torque output end of the first-stage planet carrier 9 is located on one side opposite to the transmission shaft 5, the transmission shaft 5 and the torque output end of the first-stage planet carrier 9 are coaxial, and the output torque of the power-assisted end worm 1 sequentially passes through: the power-assisted end worm wheel 2, the transmission shaft 5, the first-stage sun wheel 6, the first-stage planetary wheel 7 and the first-stage planetary frame 9 are subjected to step-by-step speed reduction and torque increase and then transmitted to a torque output end of the first-stage planetary frame 9;

The torque output end of the first-stage planet carrier 9 is detachably and fixedly connected with a coaxial rotary final sun gear 19, a group of final planet gears 20 are meshed with the periphery of the final sun gear 19, a final gear ring 22 fixedly connected to a shell and provided with annular internal teeth is meshed with the periphery of the final planet gears 20, the final planet gears 20 are rotationally connected with the final planet carrier 18, the torque output end of the final planet carrier 18 is positioned on the opposite side of the final sun gear 19, the torque output end of the final planet carrier 18 is detachably and fixedly connected with a coaxial rotary output shaft 15, the torque output ends of the final sun gear 19 and the final planet carrier 18 and the output shaft 15 are coaxial, and the output torque of the torque output end of the first-stage planet carrier 9 sequentially passes: the final sun gear 19, the final planet gear 20, the final planet carrier 18 and the output shaft 15 are transmitted to the output shaft 15 after the final sun gear 19, the final planet gear 20, the final planet carrier 18 and the output shaft 15 are subjected to step-by-step speed reduction and torque increase;

The stator of the torque rotation angle sensor 23 is fixedly connected with the outer circumference of the input shaft 24, the rotor of the torque rotation angle sensor 23 is fixedly connected with the outer circumference of the hand-force end worm 11, the torque rotation angle sensor 23 and the motor controller 27 are electrically connected to the vehicle-mounted ECU, the torque rotation angle sensor 23 outputs the electric signals of the detected torque and rotation angle to the vehicle-mounted ECU, and the motor controller 27 is electrically connected to the vehicle-mounted ECU; the torque of the motor is converted into large torque power assistance suitable for steering of the commercial vehicle through twice speed reduction and torque increase, the hydraulic system is completely abandoned by completing steering power assistance of the commercial vehicle in a pure electric power assistance mode, the problems that the hydraulic steering system of the conventional commercial vehicle steering power assistance system is high in energy consumption and easy to leak and environment-friendly are solved, and the cost of the system can be improved due to the reduction of parts of the hydraulic system, and the arrangement and matching of the steering system on the whole vehicle are easier.

Further, the hand worm 11 is meshed with a hand worm wheel 10, the hand worm wheel 10 is detachably connected with the torque output end of the first-stage planet carrier 9, and the hand worm wheel 10 and the torque output end of the first-stage planet carrier 9 are coaxial; the hand-force end worm 11 and the hand-force end worm wheel 10 are connected with the torque output end of the first-stage planet carrier 9 in a torque mode, so that the power-assisted reverse torque can be transmitted to an automobile steering wheel in real time through the hand-force end worm 11 and the input shaft 24, and a driver can feel steering torque feedback in real time.

Furthermore, the torque output end of the first-stage planet carrier 9 is detachably and fixedly connected with the final-stage sun gear 19 in the following connection mode: spline connection; the torque output end of the final stage planet carrier 18 is detachably fixedly connected with the output shaft 15 in the following connection mode: spline connection; the first-stage planet carrier 9 torque output end is detachably connected with the hand-force end worm wheel 10 in the following connection mode: the shaft holes are connected in an interference way; the spline connection ensures effective transmission of torque, and the requirement on axial connection precision is not high, so that processing and matching between a shaft and a planet carrier torque output end are simpler, more convenient and more reliable, and the shaft hole interference connection matching enables the hand-force end worm wheel 10 to be directly pressed on the planet carrier torque output end so as to effectively transmit torque, so that the processing and matching are simpler and more reliable.

Further, the group of first-stage planetary gears 7 is provided with two to six planetary gears, and the planetary gears are distributed around a rotating shaft of a torque output end of the first-stage planetary frame 9; because the cooperation between the sun gear, the planet gears and the star frame both requires speed reduction and torque increase, the number of teeth of the sun gear is smaller than that of the planet gears, the number of teeth of the planet gears is smaller than that of the inner gear ring, and the planet gears transmit larger torque, so that the torque transmission effect of a single planet gear is poor, the optimal range is two to six planet gears which are annularly and uniformly distributed, the speed reduction ratio can be ensured, and the torque bearing capacity can be ensured.

Further, the set of final planet gears 20 is provided with two to six planet gears, which are arranged around the rotation axis of the torque output end of the final planet carrier 18.

Further, the shell comprises a main shell 8 and a lower shell 21, wherein the main shell 8 is in a groove shape, the lower shell 21 is in a cover shape, and the planetary gear electric power steering gear is sealed after the lower shell 21 is buckled on the main shell 8; the output end of the output shaft 15 extends out of the lower housing 21, and the input end of the input shaft 24 and the input end of the booster end worm 1 extend out of the main housing 8.

Furthermore, an annular locking screw plug 3 is arranged at the end face of the transmission shaft 5, which is rotationally connected with the shell, and a locking nut 13 is sleeved at the position of the output shaft 15, which extends out of the shell; the locking screw plug 3 is screwed into the main shell 8 to axially position the transmission shaft 5, the locking nut 13 is screwed into the shell along the output shaft 15 and is glued, so that a gap between the output shaft 15 and the shell can be sealed and leak-proof, and lubricating oil in the power steering gear is prevented from exuding and external dust and sundries are prevented from entering the shell.

Further, bearings are respectively arranged at the positions of the rotary connection shells of the input shaft 24, the transmission shaft 5 and the output shaft 15, the positions of the rotary connection primary planet carrier 9 of the primary planet wheel 7 and the positions of the rotary connection final planet carrier 18 of the final planet wheel 20 are respectively provided with bearings.

Furthermore, the bearing of the transmission shaft 5 rotationally connected with the shell adopts a first deep groove ball bearing 4; the bearing of the final planet wheel 20 rotationally connected with the final planet carrier 18 adopts a second deep groove ball bearing 12; the bearing of the input shaft 24 rotationally connected with the shell adopts a third deep groove ball bearing 29; the bearing of the output shaft 15 rotating and connecting with the shell is a tapered roller bearing 17; the seat rings of the tapered roller bearings are pressed into the shell, the inner rings are in interference connection with the shafts, and the bearing rings can bear axial stress within a certain range while providing good rotational connection stability.

Furthermore, two groups of tapered roller bearings 17 are arranged, and the tapered roller bearings 17 are sleeved on the outer circumference of the output shaft 15 and are installed back to back along the axial direction; the tapered roller bearings 17 are installed back to back in the axial direction, and more effectively counteract the axial stress of the output shaft.

Examples

In the embodiment, the electric power steering gear mainly comprises a torque rotation angle sensing mechanism, a worm and gear speed reducing mechanism, a motor controller and a planetary gear transmission mechanism.

When a driver rotates a steering wheel, steering torque is applied to a steering system through an input shaft 24, a corresponding torsion bar 28 generates torsion deformation, the deformation angle is detected by a torque rotation angle sensor 23 and is transmitted to a motor controller 27, the motor controller 27 supplies power through a whole vehicle storage battery, meanwhile, the whole vehicle storage battery receives whole vehicle signals (vehicle speed, engine state and the like) through a CAN wire, current power-assisted demands are respectively calculated according to the current vehicle speed, steering torque and the like, the current power-assisted demands are controlled, the power-assisted torque is transmitted to a power-assisted worm wheel 2 through a power-assisted worm 1, the power-assisted worm wheel 2 is fixedly connected with a transmission shaft 5, the transmission shaft 5 transmits to a first-stage sun wheel 6, the torque is transmitted to a first-stage planet carrier 9 through a first-stage planet wheel 7, and the first-stage planet carrier 9 is in spline connection with a final-stage sun wheel 19; the hand-force end worm wheel 10 is fixedly connected with the first-stage planet carrier 9, the hand force of the driver is applied to the hand-force end worm wheel 10 through the hand-force end worm 11, and two paths of assistance force are superposed on the final-stage sun wheel 19; torque is transferred to the final planet carrier 18 via final planet wheels 20; the final stage planet carrier 18 is in spline connection with the output shaft 15, torque is transmitted to the rocker arm through the output shaft 15, and then the torque is transmitted to the wheel steering mechanism through a series of link mechanisms to push the wheels to swing, so that the steering action of the whole vehicle is realized.

The two-stage planetary gear superposition transmission is adopted, so that the transmission ratio of the product can be effectively improved, and the application requirement of a medium-heavy truck can be met; the higher helping hand rotational speed of hand power end feeds back to the motor through first grade planetary mechanism after passing through worm wheel speed reduction, has effectively avoided the phenomenon that the rotational speed that medium heavy truck steering gear transmission ratio is big to lead to is higher than the rated rotational speed of motor.

Abbreviations in this embodiment:

And (3) ECU: electronic Control Unit electronic controller unit

CAN: controller Area Network control unit area network

EPS: electronic Power Steering electric power steering system.

In summary, the utility model provides the planetary gear electric power assisted steering device for the commercial vehicle, which takes the whole vehicle storage battery as a power source, completely abandons a hydraulic system, solves the problems of high energy consumption, easy leakage and unfriendly environment of the hydraulic steering system, and can improve the cost of the system and make the arrangement and matching of the steering system on the whole vehicle easier because of reducing the parts of the hydraulic system.

It is emphasized that: the above embodiments are merely preferred embodiments of the present utility model, and the present utility model is not limited in any way, and any simple modification, equivalent variation and modification made to the above embodiments according to the technical substance of the present utility model still fall within the scope of the technical solution of the present utility model.

Claims (10)

1. A planetary gear electric power steering for a commercial vehicle, comprising: the motor control device comprises a motor controller (27), an input shaft (24) and an output shaft (15), wherein the power input end of the input shaft (24) is connected to an automobile steering wheel, the power output end of the output shaft (15) is connected to a rocker shaft for providing power for automobile steering, a torsion bar (28) and a torque rotation angle sensor (23) are arranged on the input shaft (24), and the torque rotation angle sensor (23) is electrically connected to the motor controller (27), and is characterized in that:

The motor controller (27) drives the assistance end worm (1) to rotate through the output shaft of the motor, the assistance end worm (1) is meshed with the assistance end worm wheel (2), the assistance end worm wheel (2) is fixedly connected with a coaxially rotating transmission shaft (5), a coaxially rotating first-stage sun gear (6) is fixedly connected to the transmission shaft (5), a group of first-stage planetary gears (7) are meshed on the periphery of the first-stage sun gear (6), a first-stage gear ring (26) fixedly connected to a shell and provided with annular inner teeth is meshed on the periphery of the first-stage planetary gears (7), the first-stage planetary gears (7) are rotationally connected with a first-stage planet carrier (9), a torque output end of the first-stage planet carrier (9) is located on one side opposite to the transmission shaft (5), the torque output end of the transmission shaft (5) and the first-stage planet carrier (9) is coaxial with a rotation shaft, and the output torque of the assistance end worm (1) sequentially passes through: the power-assisted end worm wheel (2), the transmission shaft (5), the first-stage sun wheel (6), the first-stage planet wheel (7) and the first-stage planet carrier (9) are subjected to step-by-step speed reduction and torque increase and then transmitted to a torque output end of the first-stage planet carrier (9);

The torque output end of the first-stage planet carrier (9) is detachably fixedly connected with a coaxial rotary final-stage sun gear (19), a group of final-stage planet gears (20) are meshed with the periphery of the final-stage sun gear (19), a final-stage gear ring (22) fixedly connected to a shell and provided with annular inner teeth is meshed with the periphery of the final-stage planet gears (20), the final-stage planet gears (20) are rotationally connected with the final-stage planet carrier (18), the torque output end of the final-stage planet carrier (18) is located at one side opposite to the final-stage sun gear (19), the torque output end of the final-stage planet carrier (18) is detachably fixedly connected with a coaxial rotary output shaft (15), the torque output ends of the final-stage sun gear (19) and the final-stage planet carrier (18) are coaxial with the output shaft (15), and the output torque of the torque output end of the first-stage planet carrier (9) sequentially passes through: the final sun gear (19), the final planet gear (20), the final planet carrier (18) and the output shaft (15) are subjected to step-by-step speed reduction and torque increase again and then transmitted to the output shaft (15);

The torque rotation angle sensor (23) is characterized in that a stator of the torque rotation angle sensor (23) is fixedly connected with the outer circumference of the input shaft (24), a rotor of the torque rotation angle sensor (23) is fixedly connected with the outer circumference of the hand-force end worm (11), the torque rotation angle sensor (23) and the motor controller (27) are electrically connected to the vehicle-mounted ECU, the torque rotation angle sensor (23) outputs electric signals of detected torque and rotation angle to the vehicle-mounted ECU, and the motor controller (27) is electrically connected to the vehicle-mounted ECU.

2. A planetary electric power steering gear for a commercial vehicle according to claim 1, wherein the hand worm (11) is meshed with a hand worm wheel (10), the hand worm wheel (10) is detachably connected with the torque output end of the first-stage planet carrier (9), and the hand worm wheel (10) and the torque output end of the first-stage planet carrier (9) are coaxial.

3. The planetary electric power steering gear for a commercial vehicle according to claim 2, wherein the torque output end of the first-stage planet carrier (9) is detachably and fixedly connected with the final-stage sun gear (19) in a connection mode that: spline connection; the torque output end of the final stage planet carrier (18) is detachably fixedly connected with the output shaft (15) in the following connection mode: spline connection; the torque output end of the first-stage planet carrier (9) is detachably connected with the hand-force end worm wheel (10) in the following connection mode: the shaft holes are connected in an interference mode.

4. A planetary electric power steering for a commercial vehicle according to claim 1, characterized in that the set of primary planetary wheels (7) is provided with two to six planetary wheels, which are arranged around the rotational axis of the torque output of the primary planetary carrier (9).

5. A planetary electric power steering for a commercial vehicle according to claim 1, characterized in that the set of final stage planets (20) is provided with two to six planets, which planets are arranged around the rotational axis of the torque output of the final stage planet carrier (18).

6. The planetary electric power steering gear for a commercial vehicle according to claim 1, wherein the housing comprises a main housing (8) and a lower housing (21), the main housing (8) is in a groove shape, the lower housing (21) is in a cover shape, and the planetary electric power steering gear is enclosed after the lower housing (21) is buckled on the main housing (8); the output end of the output shaft (15) extends out of the lower shell (21), and the input end of the input shaft (24) and the input end of the auxiliary end worm (1) extend out of the main shell (8).

7. The planetary gear electric power steering gear for the commercial vehicle according to claim 1, wherein an annular locking screw plug (3) is arranged at the end face of the transmission shaft (5) rotationally connected with the shell, and a locking nut (13) is sleeved at the position where the output shaft (15) extends out of the shell.

8. The planetary gear electric power steering gear for the commercial vehicle according to claim 1, wherein bearings are respectively arranged at the positions of the rotary connection shells of the input shaft (24), the transmission shaft (5) and the output shaft (15), and bearings are respectively arranged at the positions of the rotary connection of the first-stage planetary gear (7) with the first-stage planetary carrier (9) and the rotary connection of the last-stage planetary gear (20) with the last-stage planetary carrier (18).

9. The planetary electric power steering gear for a commercial vehicle according to claim 8, wherein the bearing of the transmission shaft (5) rotatably connected to the housing adopts a first deep groove ball bearing (4); the bearing of the final-stage planet wheel (20) rotationally connected with the final-stage planet carrier (18) adopts a second deep groove ball bearing (12); the bearing of the input shaft (24) rotationally connected with the shell adopts a third deep groove ball bearing (29); the bearing of the output shaft (15) rotationally connected with the shell is a tapered roller bearing (17).

10. A planetary electric power steering gear for a commercial vehicle according to claim 9, characterized in that the tapered roller bearings (17) are provided in two groups, and the tapered roller bearings (17) are sleeved at the outer circumference of the output shaft (15) and mounted back to back in the axial direction.